SOLUTION: axb=-144 a+b=-7 solve using algebra?

Question 703345: axb=-144
a+b=-7
solve using algebra?
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
axb=-144
a+b=-7
==============
Use * (Shift 8) for multiply
a*b=-144
a+b=-7
--------
Find 2 factors of 144 that differ by 7, one +, one minus.
---
Factors:
1*144
2*72
3*48
4*36
6*24
8*18
9*16 difference = 7
--> -16 and 9
===================
Using algebra:
a*b=-144
a+b=-7 --> b = -a-7
Sub for b in the 1st eqn
a*(-a-7) = -144

Now find 2 factors of -144 that differ by 7, same as above.
(a + 16)*(a - 9) = 0
a = 9, b = -16 or vice versa
same answer
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